Face seals of many different types have been proposed for a variety of applications over the years. One typical application is that of a sealing assembly for a machine or other device having a rotating shaft where oil, water or other fluid must be sealed from other cavities in the assembly. Generally, however, face seals such as those exemplified in U.S. Pat. Nos. 4,457,521; 3,796,507; and 3,652,183 have been formed of a length that limits the performance of the machine.
In particulr, face seals are known to create spans between bearings and other components causing the critical speeds of the rotating system to fall into the running range of the machine. One example of the adverse effects of the length of a face seal is the overhang that has been required in the cantilevered arrangement of a turbine. In addition, the face seal between a conventional bearing and sundyne pump is of a length sufficient to cause an overhang detrimental to the performance characteristics of the overall rotating system.
In making a face seal for such applications, a problem is to reduce the overhang in the turbine, pump or other machine by reducing the length of the seal. It is a related problem to increase the critical speeds of the turbine, pump or other machine to a point well above the normal running range. Moreover, another problem is to simplify the design of the face seal while reducing the weight and cost without any detrimental impact on the sealing function.
While overcoming problems of this type, it is also desirable to provide a face seal in a sealing assembly for a device having a rotatable shaft with improved efficiency. It is also desirable to provide a seal having long term reliability whether utilized in a device running continuously or one that might only be used at an indeterminate point in the future such as a missile stored in a silo for many years. Further, it is desirable to provide high integrity sealing characteristics in a face seal requiring no secondary sealing components to be utilized.
The present invention is directed to overcoming the above stated problems and accomplishing the stated objects.